Shutter arrangement for access to a paper path of a single sheet printer or copier

ABSTRACT

A shutter device enables access to the paper path in a single sheet printer with a first shutter (P 1 ) which can pivot about a first pivotal axis (D 2 ) into an open position wherein shutter stands at a distance from the paper path and uncovers an opening. A second shutter (P 2 ) is located near the first shutter (P 1 ). Like the first shutter, the second shutter forms, when in an operating position, a second of the guide surfaces adjacent to the section formed by the first shutter (P 1 ), which can pivot about a second pivotal axis (D 1 ) into an open position and increase an opening for access to the paper path when in this position. In order to support opening of the second shutter (P 2 ), a clamping member (Z 1 ) is also provided on the second shutter, which is prestressed when the second shutter (P 2 ) is in the operating position.

FIELD OF THE INVENTION

The invention is directed to a shutter arrangement for access to a paperpath of single sheet printers and copiers.

BACKGROUND OF THE INVENTION

Paper jams occasionally occur in the paper path of single sheet printersand copiers. In any case, the paper path must be at least partiallyuncovered in order to remove jammed sheets. For the sake of simplicity,only single sheet printers shall be mentioned below instead of singlesheet printers and copiers; not only paper but also other printingmatter can be processed with single sheet printers, whereby only paperjam, paper material and the like shall be mentioned below.

In order to remove jammed sheets from the paper path, it is known, forexample, to arrange shutters along the paper path that form a part ofthe guide surface of the paper path in the closed condition and that canbe pivoted away from the paper path in the case of a paper jam so thatthe user can remove the jammed sheets.

U.S. Pat. No. 4,116,556, thus, discloses a copier device wherein ashutter arrangement is provided for removing potential paper jams in thearea of the photo conductor drum. The shutter arrangement is composed oftwo shutters connected to one another via an articulation, the onethereof being seated at the housing of the copier device pivotablearound a swivelling axis. The two shutters can be adjusted in commonbetween an operating position wherein they form a guide surface for thepaper path and an open position wherein the shutters are swivelled awayfrom the paper path and release a lateral interspace between the paperpath and the shutters through which the jammed sheets can be removed. Acomparable shutter arrangement having two shutters pivotably seated atthe housing is also disclosed by U.S. Pat. No. 4,478,506 or,respectively, by JP-57 151 954 A.

Given these known shutter arrangements, the shutters can in fact beswivelled away from the paper path in order to enable access into thepaper path. The interspace between the paper path and the shuttersproduced for the access, however, is comparatively small due to thesmall structural volume of such copier devices, so that the jammedsheets can only be removed from the paper path under more difficultconditions and with a great expenditure of time.

Therefore, there is a need for a shutter arrangement for single sheetprinters and copiers that can be unproblematically opened and enablessimple access to the paper path.

SUMMARY OF THE INVENTION

In an embodiment, the shutters swivelled into the open position releasean opening for the access, and in that at least one tension element isprovided at the second shutter that is pre-stressed in the operatingposition of the second shutter and supports the opening movement thereofinto the open position due to the pre-stressing force.

In the invention, the shutters swivelled in common into the openposition release an opening through which the sheets jammed in the paperpath can be removed in a simple and comfortable way. Further, theopening of the shutters is facilitated by the tension element thatpromotes the opening movement of the second shutter. When, by contrast,the second shutter is swivelled into the operating position, it ismechanically clamped by the pre-stressing force exerted by the tensionelement and is held in a defined position in this way.

It is fundamentally possible to equip each of the two shutters with aseparate lock and with its own actuation means, that must be separatelyactuated for each shutter. According to a development of the invention,however, it is advantageous that the second shutter is pivotable by theactuation means together with the first shutter, so that operation issimple and takes little time.

It would then be possible to provide a higher-ranking actuation andlocking means that, for example, is connected to each of the twoshutters via a rodding. An especially simple and expedient developmentof the invention is then comprised therein that the second shutter isfashioned and trainable by the first shutter.

The first swivelling axis can be displaceably arranged on, for instance,a pivotably seated carrier, so that the first shutter can be swivelledaround obstacles in this way.

In a preferred embodiment, the first swivelling axis is stationarilyarranged at the single sheet printer. In order to be able to pivot thefirst shutter around an obstacle, it potentially has a projecting web atthe backside, i.e., at the side facing away from the paper path, whosefree end edge is penetrated by the swivelling axis.

It is also proposed to seat the second shutter pivotably at the firstshutter and to provide a tension spring as a tension element that hasits one end secured to the first shutter and has its other end securedto the second shutter, so that the second swivelling axis also swivelswhen the first shutter is swivelled. As a result of the tension spring,the two shutters are secured such that, in their operating position, itstresses these toward one another between their guide surfaces and thesecond swivelling axis. The movement of the second shutter in at leastthe one direction, namely when opening the shutters, can thus becontrolled in a simple and dependable way.

In another preferred, second embodiment, the second swivelling axis isalso stationarily arranged at the single sheet printer and a tensionspring is provided as tension element that has its one end stationarilysecured at the single sheet printer and has its other end secured to thesecond shutter. Two separate shutters are thus provided that, likewindow shutters, are hinged at both sides of the access opening of thepaper path.

The shutters, for example, can be shaped of deep-drawn sheet metal orcan be cast in one piece. According to a development of the invention,it is especially advantageous that the two shutters are parts ofprofiled ledges that extend transversely relative to the paper path.

Such profiled ledges can be manufactured of plastic or lightweight metalwith high precision and surface quality in an economical way and areprovided as desired with versatile stiffening means.

In a preferred embodiment of the invention, the actuation means is alocking rod seated in the first shutter and extending transverselyrelative to the paper path that engages into an abutment stationarilyattached to the single sheet printer and comprises a draw-button forunlocking.

The first shutter is thus positively held in its respective lockedposition; the locking rod can be actuated from the outside of themechanism of the single sheet printer via the draw-button. Given acorrespondingly rigid shutter, it is adequate to lock this at only oneside. A reliable holding of the shutter is achieved in a development ofthe invention in that an abutment is arranged at both sides of the firstshutter.

In the first of the alternative embodiments recited above, a bearingplate is attached to the first shutter for improved stiffening of theprofiled ledge and for bearing additional elements, this bearing plateextending transversely to the first shutter from the side facing awayfrom the guide surface. At its side facing away from the guide surface,the second shutter comprises a projecting web at whose end the secondswivelling axis is provided, whereby the second swivelling axis isconnected to the projecting part of the bearing plate.

A rodding that sees to the motion control of the second shutter can bearranged between the first shutter that comprises the actuation meansand the second shutter.

Since the first shutter is fixed in its operating position by lockingthe actuation means, the support of the second shutter in the operatingposition can ensue via the first shutter. Further, a stationary abutmentis provided that supports the second shutter in its operating position.This sees to a stable and precise final position of the second shutter.

The abutment is advantageously composed of a stationary connecting linkthat is provided for accepting and for supporting a sliding pad that isattached to the second shutter. When swivelling the second shutter intothe operating position, the sliding pad engages into the connecting linkand supports the second shutter.

The connecting link is preferably arranged close to the end of thesecond shutter that faces away from the first shutter. The connectinglink comprises two parallel guide webs that preferably extend parallelto the guide surface of the second shutter, whereby the guide web facingaway from the second shutter is shortened such that the sliding pad canbe pivoted out of the connecting link preceding this guide web when thetwo shutters are opened and runs up against the longer guide web whenthe shutters are closed and can be moved therefrom into the connectinglink.

The limitation of the open limit position of the second shutter on thefirst could ensue with a catch, an interlock or a suitable arrangementof the tension spring. An especially simple and reliable embodiment,however, is comprised in providing a stop on the bearing plate. Thesecond shutter is thereby pulled against the stop by the tension springand thus dependably assumes its limit position.

In especially expedient arrangement of the aforementioned, secondembodiment, wherein both shutters are respectively attached in astationary pivot bearing at both sides of the opening, the secondshutter comprises a projecting web at its back side which faces awayfrom the first shutter and the second swivelling axis is connected tothe free end of said projecting web, and that the second swivelling axisintersects a straight line proceeding through both ends of the tensionspring in the open position of the second shutter. The tension springthus holds the second shutter in its open position, so that anadditional stop or an interlock for the second shutter is not required,even when it is released from engagement with the first shutter in itsopen position.

Only one stop which, however, must be controlled by the first shutter,is required in order to retain the second shutter in its operatingposition opposite the force of the tension spring. To this end, acontinuation that engages behind the second shutter in the operatingposition is arranged on the first shutter, this continuation alsoholding the second shutter in its operating position when the firstshutter is locked.

The continuation preferably not only serves to hold the second shutterclosed, i.e., in its operating position, but is also lengthened suchthat it engages behind the second shutter when the first shutter isclosed and thus entrains the second shutter into the closed operatingposition.

Only a single tension spring and a rigid continuation thus suffice inorder to fully couple the second shutter with the first shutter in itsclosing and opening motion, whereby the dependability is enhanced due tothe simple structure.

The continuation could, for example, be fashioned as a pin that isscrewed into the profiled rod forming the first shutter. An especiallysimple but stable design is comprised therein that the continuation isfashioned at a plate that extends transversely relative to the firstshutter and is attached to the backside thereof. The broad butthin-walled continuation of sheet metal that is loaded in a directiontransversely relative to the thickness of its wall forms a lightweight,flexurally rigid element. The sheet metal also in turn stiffens theprofiled rod that forms the first shutter.

The continuation can engage behind a second sliding pad that isfashioned at the second shutter. It is also possible to fashion thesecond shutter longer than the first, so that the continuation engagesbehind the second shutter.

A preferred development of the invention is comprised therein that thecontinuation attacks at the articulation of the tension spring and isarranged laterally next to the second shutter or opposite a slottherein, so that the pivot paths of the second shutter and of thecontinuation can overlap. All forces applied onto the second shutter arethus introduced into the tension spring articulation. The second shutteritself remains essentially unloaded and can thus be implemented light.

In an embodiment, the present invention provides a shutter assembly fora paper path of a single sheet printing or copying device, the shutterassembly comprising a first shutter pivotably mounted to the deviceabout a first axis, the first shutter comprising a first guide surfacefor the paper path when the first shutter is in a first operatingposition, the first shutter being pivotable to a first open positionwherein the first guide surface is clear of the paper path, the firstshutter being connected to a locking rod which releasably engages thedevice for locking the first shutter in the first operating position,the shutter assembly also comprising a second shutter pivotably mountedto the device about a second axis, the second shutter comprising asecond guide surface for the paper path that is in alignment with thefirst guide surface of the first shutter when the second shutter is in asecond operating position, the second shutter being pivotable betweenthe second operating position and a second open position wherein thesecond guide surface of the second shutter is clear of the paper path,the second shutter being connected to at least one tension element thatbiases the second shutter towards the second open position, the firstshutter engaging the second shutter when the first shutter is in thefirst operating position and the first shutter effectively locking thesecond shutter in the second operating position when the first shutteris locked into the first operating position by the locking rod.

In an embodiment, movement of the first shutter to the first openposition results in movement of the second shutter to the second openposition.

In an embodiment, movement of the first shutter to the first operatingposition results in movement of the second shutter to the secondoperating position.

In an embodiment, the first axis comprises a pin that is stationarilyconnected to the device.

In an embodiment, the second shutter is pivotably connected to the firstshutter at the second axis, and the tension element comprises a tensionspring with one end connected to the first shutter and a second endconnected to the second shutter.

In an embodiment, the second axis comprises a pin stationarily connectedto the device, and the tension element comprises a tension spring withone end connected to the device and another end connected to the secondshutter.

In an embodiment, the first and second guide surfaces of the first andsecond shutters extend transversely relative to the paper path.

In an embodiment, the locking rod extends transversely relative to thepaper path, the locking rod engaging two abutments connected to thedevice at opposing sides of the first shutter, the locking rodcomprising a draw-button at one end for unlocking the locking rod fromone of said abutments.

In an embodiment, the first shutter is connected to a bearing plate, thebearing plate extending away from the paper path and towards the secondshutter, the second shutter comprising a projecting web that extendsaway form the paper path, the second axis extending through theprojecting web, the second axis passing through the bearing plate.

In an embodiment, the second shutter engages a stationary abutment whenthe second shutter is in the second operating position.

In an embodiment, the second shutter comprises a sliding pad and theabutment comprises a stationary connecting link configured for receivingthe sliding pad when the second shutter moves into the second operatingposition.

In an embodiment, the bearing plate comprises a stop, the stopprojecting into a path of the second shutter as the second shutter movesfrom the second operating position to the second open position, the stopengaging the second shutter and limiting movement thereof when thesecond shutter reaches the second open position.

In an embodiment, the second shutter comprises a projecting web thatextends away from the paper path and the first shutter, the projectingweb comprising a free end of said web through which the second axisextends, and in the second open position of the second shutter, astraight line proceeding through the two ends of the tension springintersects the second swivelling axis.

In an embodiment, the first shutter comprises a continuation member thatengages the second shutter when the first and second shutters are in thefirst and second operating positions respectively, the continuationmember holding the second shutter in its second operating position whenthe first shutter is locked in its first operating position.

In an embodiment, the continuation element engages the second shutter asthe first shutter is moved from the first open position to the firstoperating position thereby moving the second shutter into the secondoperating position.

In an embodiment, the continuation member comprises a plate that extendstransversely relative to the first shutter, the first shutter comprisinga backside, the continuation member being connected to the backside.

In an embodiment, the continuation member engages the tension spring andis disposed laterally adjacent to the second shutter so that, duringmovement of the first shutter from the first open position to the firstoperating position, the continuation member engages the second shutter.

The invention is not limited to the exemplary embodiments recited aboveand to an arrangement having two shutters. For example, each shutter canbe actuated and locked separately, and more than two shutters can beprovided. For example, it would be possible to arrange two shutters atboth sides of an opening, at least one thereof being in turn composed oftwo shutters as described in the above explanation.

Other objects and advantages of the present invention will becomeapparent from reading the following detailed description and appendedclaims, and upon reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in detail below on the basis of preferredexemplary embodiments with reference to the drawings, wherein;

FIG. 1 is a schematic longitudinal view of a first embodiment of theinventive shutter arrangement, in its operating position;

FIG. 2 illustrates the shutter arrangement of FIG. 1 in the openposition;

FIG. 3 illustrates the shutter arrangement of FIG. 1 during opening orclosing;

FIG. 4 is a schematic longitudinal view of a second embodiment of theinventive shutter arrangement, in operating position,

FIG. 5 illustrates the shutter arrangement of FIG. 4 in open position;and

FIG. 6 illustrates the shutter arrangement of FIG. 4 during opening orclosing.

It should be understood that the drawings are not necessarily to scaleand that the embodiments are sometimes illustrated by graphic symbols,phantom lines, diagrammatic representations and fragmentary views. Incertain instances, details which are not necessary for an understandingof the present invention or which render other details difficult toperceive may have been omitted. It should be understood, of course, thatthe invention is not necessarily limited to the particular embodimentsillustrated herein.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Reference characters that are entered into one of the respectively threeFIGS. 1 through 3 or, respectively, 4 through 6 are respectivelycorrespondingly valid for all three figures.

FIG. 1 shows a plurality of paper paths in a side view as broken lines,these being limited by clamp or, respectively, conveyor rollers 3. Thepaper paths are limited by guide surfaces for the individual sheets;these guide surfaces are not shown here with the exception of an arcuatesection, whereby the guide surface is formed by the outside surface oftwo shutters P1, and P2 adjoining one another when they are in theoperating position shown in FIG. 1. The two shutters P1 and P2 arelocated between clamp roller pairs 3 or the paper path.

Both shutters P1, and P2 are formed of a profiled rod that respectivelyextends transversely relative to the paper path. The first profiled rodP1 is formed of a hollow profile that is formed by the outside walladjoining the paper path having an arcuate cross section, an inside wallconnecting its two ends tendon-like and of a stiffening portion thatconnects the approximate center points of the outside wall and theinside wall to one another. Close to the first pivot point, alsoreferred to as a first swivelling axis, D2, the inside wall therebycomprises a flat gutter 10 with which it embraces the neighboring clamproller in the open position (FIG. 2).

A first swivelling axis D2 extends along the first shutter P1 at theintersection of the inside wall and the outside wall that lies closestthe one clamp roller pair. At the location of the swivelling axis, theprofiled rod forming the first shutter P1 comprises a bore similar to aprofiled section into which pivot pegs can be inserted at the ends ofthe profiled rod, these pivot pegs being accepted in stationary bearingsof the single sheet printer (not shown).

A further fashioning 11 of the profiled rod similar to a bore is locatedat the junction of outside wall and stiffening. This configuration ispenetrated by a locking rod V1 that comprises an actuation knob at atleast one end of the first shutter P1, this serving the purpose—by beingpulled or pushed in—of moving the locking rod V1 in its longitudinaldirection (in the profiled direction of the first shutter P1) such thatit is released from the mounts (not shown) that are stationarilyarranged at both sides of the first shutter. In its quiescent position,the locking rod V1 holds the first shutter P1 locked in the operatingposition shown in FIG. 1.

At one or both ends of the first shutter P1, a bearing plate L is put inplace thereon that provides the stiffening as well as the part of theprofile that faces away from the first swivelling axis D2. The bearingplate extends far beyond the inside wall of the profile and forms atriangular leg whose tip pointing away from the first shutter P1 ispenetrated by a second swivelling axis D1, and whereby a stop A (FIG. 2)that projects at the side of the bearing plate L facing toward the firstshutter P1 is arranged in the middle thereof.

A spring articulation 12 that has its end projecting beyond the firstshutter P1 and the bearing plate L is located at the junction of theinside wall and the stiffening.

The outside wall of the first shutter P1 adjoins at an arcuate section aof the paper path that is followed by a straight section b at which awall of a second shutter P2 adjoins. At its edge facing toward the firstshutter P1, this wall is bent away from the paper path and overlaps thatside of the first shutter P1 facing toward the paper path thereat.

At the backside of the second shutter P2, distanced from its curved edgeby about one-third of its length (that proceeds in conveying directionof the paper sheet), a first web 20 extending in the profile directionthereof projects therefrom, this exhibiting a length that corresponds tonearly half the length of the shutter.

A thickened portion having an interior similar to a bore is fashioned atthe free edge of the first web, a second swivelling axis D1 that lies onan imaginary line between the swivelling axis D2 and a sliding pad Gproceeding therethrough. This thickened portion is overlapped at bothends by the tip of the bearing plate L of the first shutter P1; a pivotpeg respectively secured to this bearing plate L extends into theinterior of the thickened portion.

A second web 21 whose free edge is fashioned just like that of the firstweb projects from the backside of the shutter close to the edge of thesecond shutter P2 that lies opposite the curved edge. The cylindricalsliding pad G that extends in the profiled direction is respectivelysecured to the ends of this free edge.

A respective spring articulation 22 is fashioned at the end at thebackside of the wall of the second shutter P2 approximately in themiddle between the two webs 20 and 21. A tension spring Z1 extends ateach of the ends of the two shutters P1 and P2 between the two springarticulations 12 and 22 of the two shutters P1 and P2.

A stationary guide F like a connecting link is arranged at one side ofthe second shutter P2 and has a long guide web F1 parallel to theneighboring paper path and a short guide web F2 that is arranged at theside of the long guide web F1 remote from the paper path and parallelthereto. The distance between the two guide webs F1 and F2 isdimensioned such that the sliding pad G is displaceably guided betweenthese and practically free of play.

In the operating position of FIG. 1, the sliding pad G is seated betweenthe two guide webs F1 and F2, so that the second shutter P2 is retained,first, by the guide F and, second, by the second swiveling axis D1 thatis in turn fixed in place because the locking rod V1 retains the firstshutter P1 in its operating position.

When the locking rod V1 is released and when the first shutter P1 isopened up with its manipulation (counter-clockwise in FIG. 1), theswivelling axis D1 moves away from the paper path b and entrains thesecond shutter P2. As can be seen from FIG. 3, this is stressed such bythe tension spring Z1 that it is pivoted around the swivelling axis D1in a clockwise direction, whereby the sliding pad G is pressed againstthe guide web F1 of the guide F until the second shutter P1 has itsfirst web 20 lying against the stop A FIG. 2). This intermediateposition is shown in FIG. 3 wherein the arrow f illustrates the pressingpower of the sliding pad G against the guide web F1.

The sliding pad G has thereby moved along the guide web F1 by the lengthof the arrow e in the meantime and has thereby emerged from theengagement region of the retaining web F2. When the swivel motion of thelocking rod V1 is then continued, the open position shown in FIG. 2 isultimately achieved, whereby the sliding pad G traverses the motion pathg shown dot-dashed.

In this open position, the locking rod V1 can again be locked at thesingle sheet printer, so that the shutter arrangement remains in theopen position shown in FIG. 2.

When being closed, the sliding pad G strikes against the guide web F1 ofthe guide F and subsequently moved there along until it proceeds intothe interspace between guide web F1 and retaining web F2. The firstshutter P1 is then locked with the locking rod V1 and holds it fast incollaboration with the guide F. That edge of the second shutter P2remote from the first shutter P1 thereby engages into the draw-in regionbetween the adjoining clamp rollers of the paper path. Only theinventive arrangement composed of the two shutters P1 and P2 can producean opening having such a great width that facilitates access to thepaper path, since the second shutter P2 is first pivoted out of itsoperating position toward the first shutter P1 before it is completelypivoted away from the paper path together with the first shutter P1.

FIGS. 4 through 6 show a second embodiment of the shutter arrangementthat is attached to a paper path limited by two clamp roller pairs 4 and5 and slightly angled off roughly in the middle between these.

The paper path is limited by two shutters P4 and P3 in their operatingposition, both of these shutters P1 and P2, as described above, beingcomposed of profiled rods that extend transversely relative to the paperweb.

The first shutter P4 comprises a wall that is adapted to the course ofthe paper web and extends from the first clamp roller pair 5 to beyondthe middle of the distance to the second clamp roller pair 4. Thelateral edge of the first shutter P4 that faces toward the first clamproller pair 5 is curved slightly away from the paper path in order tofacilitate the entry of the paper web at this location.

A fashioning with an interior similar to a bore is located at thebackside of the wall (the side facing away from the paper path) close tothe edge that is curved away, a first swivelling axis D4 with which thefirst shutter P4 is pivotably attached to the single sheet printerextending through this interior.

A similar fashioning is attached in the middle between the two edges ofthe first shutter P4 and accepts a locking rod V2 whose structure andfunctioning correspond to the above-described locking rod V1 of thefirst embodiment and that, like the other, releasably locks the firstshutter P4 in the operating position shown in FIG. 4.

Further, a fashioning with an interior similar to a bore is respectivelyformed at that edge of the first shutter P4 facing toward the secondshutter P3 and at the free end edge of a web 40 that, for reinforcingpurposes, is attached to the backside of the wall of the first shutterP4 close to the receptacle of the locking rod V2 and projects from thewall at a right angle.

A plate B is respectively attached at both sides at the end sides of thefirst shutter P4, the plate B being carried by the web 40 and by thepart of the wall facing toward the second shutter P3 and comprising afinger projecting far in the direction of the second shutter P3 thatengages far behind the second shutter P3.

The second shutter P3 comprises a wall that extends up to a pointbetween the two first clamp rollers 4 and comprises a springarticulation at its backside roughly in the middle between the two edgesas well as guide pin. The guide pin is seated in a bore and carries aweb 30 projecting from the backside (the side facing away from the paperpath) close to the first clamp rollers. At its free end edge, the web 30has a thickened portion through whose interior the second swivellingaxis D3 proceeds, the second shutter P3 being rotatably attached to thesingle sheet printer therewith.

The edge of the wall facing toward the first shutter P4 does not extendentirely up to the first shutter P4 and is curved slightly away from thepaper web.

A tension spring Z2 has its one end hinged to the spring articulation ofthe second shutter P3 and has its other end hinged to a stationary pointof the single sheet printer. This point lies opposite the middle of thepaper path covered by the two shutters P4 and P3 spaced therefrom suchthat the track of the second swivelling axis D3 and the two hinge pointsof the tension spring Z2 lie on a straight line in the side view of FIG.5.

In the operating position of FIG. 4, the first shutter P4 is retained bythe locking rod V2, has the finger of the plate B engaging behind theguide pin of the second shutter P3 and thereby holds this in itsoperating position, even though a tensile force for opening acts on thesecond shutter P3 as a result of the tension spring Z2.

When the locking rod V2 is unlocked and when the first shutter P3 ispivoted into its open position (FIG. 5) with the handle attached to it,then the first shutter P3 is again locked in this open position with thelocking rod V2. The second shutter P4 is then released by the finger, isswivelled by the tension of the tension spring Z2 and is held in theopen position by this.

When the first shutter P4 in the open position is released by actuatingthe locking rod V2 and pivoted in, the finger becomes seated at theguide pin at the second shutter P3 and presses this in the directiontoward the paper path as shown in FIG. 6. Since this load ensues offsetrelative to the second swivelling axis D3, the guide pin yields andthereby runs along that edge of the finger adjacent to it, whereby itpivots the second shutter P3 until the shutters P4 and P3 have reachedthe operating position of FIG. 4.

In both embodiments, the profiled rods that form the shutters P1 and P4can be manufactured of plastic or metal, preferably of an aluminumalloy. The bearing plates L and plates B are attached to the two ends ofthe profiled rods at one side, these profiled rods forming the firstshutters P1 and P4.

From the above description, it is apparent that the objects of thepresent invention have been achieved. While only certain embodimentshave been set forth, alternative embodiments and various modificationswill be apparent from the above description to those skilled in the art.These and other alternatives are considered equivalents and within thespirit and scope of the present invention.

What is claimed is:
 1. A shutter assembly for a paper path of a singlesheet printing or copying device, the shutter assembly comprising: afirst shutter pivotably mounted to the device about a first axis, thefirst shutter including a first guide surface for the paper path whenthe first shutter is in a first operating position, the first shutterbeing pivotable to a first open position wherein the first guide surfaceis clear of the paper path, the first shutter being connected to alocking rod which releasably engages the device for locking the firstshutter in the first operating position; a second shutter pivotablymounted to the device about a second axis, the second shutter includinga second guide surface for the payper path that is in alignment with thefirst guide surface of the first shutter when the second shutter is in asecond operating position, the second shutter being pivotable betweenthe second operating position and a second open position wherein thesecond guide surface of the second shutter is clear of the paper path;at least one tension element connected to the second shutter that biasesthe second shutter towards the second open position; the first shutterengaging the second shutter when the first shutter is in the firstoperating position and the first shutter effectively locking the secondshutter in the second operating position when the first shutter islocked into the first operating position by the locking rod; the secondshutter being pivotably connected to the first shutter at the secondaxis, and the tension element including a tension spring with one endconnected to the first shutter and a second end connected to the secondshutter.
 2. The shutter assembly of claim 1, wherein movement of thefirst shutter to the first open position results in movement of thesecond shutter to the second open position.
 3. The shutter assembly ofclaim 2, wherein movement of the first shutter to the first operatingposition results in movement of the second shutter to the secondoperating position.
 4. The shutter assembly of claim 1, wherein thefirst axis includes a pin that is stationarily connected to the device.5. The shutter assembly of claim 1, wherein the first and second guidesurfaces of the first and second shutters extend transversely relativeto the paper path.
 6. The shutter assembly of claim 1, wherein the firstshutter is connected to a bearing plate, the bearing plate extendingaway from the paper path and towards the second shutter, the secondshutter including a projecting web that extends way form the paper path,the second axis extending through the projecting web, the second axispassing through the bearing plate.
 7. The shutter assembly of claim 6,wherein the second shutter engages a stationary abutment when the secondshutter is in the second operating position.
 8. The shutter assembly ofclaim 7, wherein the second shutter includes a sliding pad and theabutment includes a stationary connecting link configured for receivingthe sliding pad when the second shutter moves into the second operatingposition.
 9. The shutter assembly of claim 6, wherein the bearing plateincludes a stop, the stop projecting into a path of the second shutteras the second shutter moves from the second operating position to thesecond open position, the stop engaging the second shutter and limitingmovement thereof when the second shutter reaches the second openposition.
 10. A shutter assembly for a paper path of a single sheetprinting or copying device, the shutter assembly comprising: a firstshutter pivotably mounted to the device about a first axis the firstshutter including a first guide surface for the paper path when thefirst shutter is in a first operating position, the first shutter beingpivotable to a first open position wherein the first guide surface isclear of the paper path, the first shutter being connected to a lockingrod which releasably engages the device for locking the first shutter inthe first operating position; a second shutter pivotably mounted to thedevice about a second axis, the second shutter including a second guidesurface for the paper path that is in alignment with the first guidesurface of the first shutter when the second shutter is in a secondoperating position, the second shutter being pivotable between thesecond operating position and a second open position wherein the secondguide surface of the second shutter is clear of the paper path; at leastone tension element connected to the second shutter that biases thesecond shutter towards the second open position; the first shutterengaging the second shutter when the first shutter is in the firstoperating position and the first shutter effectively locking the secondshutter in the second operating position when the first shutter islocked into the first operating position by the locking rod; the secondaxis including a pin stationarily connected to the device, and thetension element including a tension spring with one end connected to thedevice and another end connected to the second shutter.
 11. the shutterassembly of claim 10, wherein the second shutter includes a projectingweb that extends away from the paper path and the first shutter, theprojecting web including a free end of said web through which the secondaxis extends; and in the second open position of the second shutter, astraight line proceeding through the two ends of the tension springintersects the second axis.
 12. The shutter assembly of claim 11,wherein the first shutter including a continuation member that engagesthe second shutter when the first and second shutters are in the firstand second operating positions respectively, the continuation memberholding the second shutter in its second operating position when thefirst shutter is locked in its first operating position.
 13. The shutterassembly of claim 12, wherein the continuation element engages thesecond shutter as the first shutter is moved from the first openposition to the first operating position thereby moving the secondshutter into the second operating position.
 14. The shutter assembly ofclaim 13, wherein the continuation member includes a plate that extendstransversely relative to the first shutter, the first shutter having abackside, the continuation member being connected to the backside. 15.The shutter assembly of claim 14, wherein the continuation memberengages the tension spring and is disposed laterally adjacent to thesecond shutter so that, during movement of the first shutter from thefirst open position to the first operating position, the continuationmember engaging the second shutter.
 16. The shutter assembly of claim10, wherein movement of the first shutter to the first open positionresults in movement of the second shutter to the second open position.17. The shutter assembly of claim 16, wherein movement of the firstshutter to the first operating position results in movement of thesecond shutter to the second operating position.
 18. The shutterassembly of claim 10, wherein the first axis includes a pin that isstationarily connected to the device.
 19. The shutter assembly of claim10, wherein the first and second guide surfaces of the first and secondshutters extend transversely relative to the paper path.
 20. A shutterassembly for a paper path of a single sheet printing or copying devicethe shutter assembly comprising: a first shutter pivotably mounted tothe device about a first axis the first shutter including a first guidesurface for the paper path when the first shutter is in a firstoperating position, the first shutter being pivotable to a first openposition wherein the first guide surface is clear of the paper path thefirst shutter being connected to a locking rod which releasably engagesthe device for locking the first shutter in the first operatingposition; a second shutter pivotably mounted to the device about asecond axis, the second shutter including a second guide surface for thepaper path that is in alignment with the first guide surface of thefirst shutter when the second shutter is in a second operating position,the second shutter being pivotable between the second operating positionand a second open position wherein the second guide surface of thesecond shutter is clear of the paper path; at least one tension elementconnected to the second shutter that biases the second shutter towardsthe second open position; the first shutter engaging the second shutterwhen the first shutter is in the first operating position and the firstshutter effectively locking the second shutter in the second operatingposition when the first shutter is locked into the first operatingposition by the locking rod; and the locking rod extending transverselyrelative to the paper path, the locking rod engaging two abutmentsconnected to the device at opposing sides of the first shutter, thelocking rod including a draw-button at one end for unlocking the lockingrod from one of said abutments.